The less harmful cigarette: a controversial issue. a tribute to Ernst L. Wynder.

The dose-response relationship between number of cigarettes smoked and risk for lung cancer was established in 1950 by epidemiological studies. Laboratory assays with tobacco tar on mouse skin and smoke inhalation experiments with hamsters provided further evidence for this relationship. In cigarette smoke, among 4800 identified compounds, 69 are carcinogens, and several are tumor promoters or cocarcinogens. The major toxic agents are nicotine, carbon monoxide, hydrogen cyanide, nitrogen oxides, some volatile aldehydes, some alkenes, and some aromatic hydrocarbons. Public health information and education have led to a reduction of cigarette smokers among U.S. adults from 40 to 25%. However, in high school students, smoking increased to 35% and in adults with less than a high school education it remains high at 33.3%. Intervention studies were augmented with attempts of risk reduction by changing the tobacco composition and makeup of cigarettes. This led to cigarettes that, according to the FTC, reduced the tar and nicotine yields from an average of 37 and 2.7 mg to 12 and 0.85 mg. The anticipated reduction of mortality rates from chronic diseases among cigarette smokers did not occur, primarily, because of a major adjustment in smoking intensity and depth of inhalation by the habitual smokers. It is, therefore, imperative that smoking control efforts are intensified and that, short of banning cigarette sales, cigarettes delivering smoke with the lowest potential for toxicity, addiction, and carcinogenicity are declared a matter of public health policy.